1. Field of the Invention
The present invention relates to a mechanism for keeping a lock device released from a movable member, the lock device being disposed in a cylinder or the like.
2. Description of the Related Art
A brake-equipped fluid pressure cylinder has conventionally had a lock device for holding a piston. A brake-equipped clamp unit has conventionally had a lock device for keeping a workpiece fixed by an arm. It is necessary for the brake-equipped fluid pressure cylinder and the brake-equipped clamp unit to temporarily release a lock device and to manually operate a workpiece upon a set up in an initial state or in an emergency.
The conventional lock device attached to the brake-equipped fluid pressure cylinder and the brake-equipped clamp unit includes means for releasing the lock. However, the conventional lock device does not include any mechanism for keeping the lock released. Therefore, the operability is unsatisfactory and is complicated in the emergency or maintenance.
Specifically, the lock device pressed by a spring or the like is manually operated against the spring for releasing the lock device. Then, an operator needs to manually operate the lock device for releasing the lock so that the spring force cannot operate the lock device because no mechanism is disposed for keeping the lock device released.
In other words, the conventional lock device attached to the brake-equipped fluid pressure cylinder and the brake-equipped clamp unit can temporarily release the lock. However, no mechanical means is disposed for keeping the lock device released for a desired period of time. Therefore, the operator prevents the conventional lock device from operating with one hand against the spring force.
It is a general object of the present invention to provide a mechanism which can keep a lock device released with a simple and convenient structure.
The above and other objects, features, and advantages of the present invention will become more apparent from the following description when taken in conjunction with the accompanying drawings in which a preferred embodiment of the present invention is shown by way of illustrative example.